Hinges of this type are available on the market, and they are employed in industrial equipment, for example for the connection of hoods of mechanical equipment to the frame, or of doors to automatic vending machines, to electric cabinets, to banking devices, or in protection carters, access gates or the like.
This type of hinge was met with considerable success on the market, also in the light of the fact that it meets the need of operators and maintenance personnel of having a gate, or a hood, which keeps an open, secure position, however chosen, and that it does not interfere—if only incidentally—with the action thereof.
The hinges thus made found on the market provide a system of mutual engagement of two hinge elements, consisting of locking elements between a central pivot and one—or both—hinge elements. Thrust springs are provided, made of steel or rubber, which are associated with further additional elements, such as for example steel spheres and screws.
U.S. Pat. No. 5,412,842 owned by Southco Inc. concerns for example a conventional-type hinge, wherein suitable means are provided apt to retain in specific mutual positions the two hinge wings. Said devices consist of a spring-sphere pair, housed in the wall-fastened wing, and of holes and grooves provided on the wings so that the sphere-shaft coupling keeps the door in a predefined secure position, unless a strong pressure is imparted on the gate.
However, such a solution is particularly complex to accomplish, since all the recesses obtained must be perfectly in axis to be able to effectively lock the gate, and since rather difficult mounting operations are necessary, with the risk that the sphere departs from its seat during the installation.
Furthermore, since the engaging means are basically made of steel, they are complex to be realized and have a poor tribologic coupling. Finally, the springs apt to drive the spheres are partially in sight: therefore, an unexpected shock could unlock them from the original position, for example during the transport phase or the mounting phase. Such an event could affect the functionality of the means.
In order to make the hinge structure simpler, the Applicant duly submitted Italian patent no. 1365898, aimed at protecting a hinge having multiple halt positions, the hinging elements of which provided on the respective wings have on the engagement surfaces ribs and longitudinal recesses in mutual engagement. This invention, which substantially provided to insert no retaining element, proved particularly useful in case of relatively light loads, but it highlighted some problems on heavier loads
In order to solve this matter, the applicant has filed the Italian patent 1398735, apt to describe a novel solution, in which the thrust element was inserted inside a slot provided on the wing without the grooved cylindrical body, and consisted of an elastic element at X ending at a wedge end. The steady engagement between the two wings was granted by the engagement of the wedge with the groove provided onto the cylindrical body and by the elastic force of an X-shaped element provided upstream the wedge element. After the application of a force to a movable door (that is, to the wall fixed to the movable door) the wedge element tends to shrink, in order to allow the detachment of the said wedge from the groove provided on the cylindrical element of the other wing.
However, also this solution appears rather difficult to realize, and shows several disadvantages during the mounting phase, because the correct placement of the engagement elements could become difficult: as a matter of fact, this kind of hinge is relatively small in size.
Furthermore, this solution appears particularly subjected to the changes in temperature and humidity of the environment in which it is used, since the elastic force of the X-shaped element it is connected to the properties of the plastic material with which it is used.
Therefore, it is object of the present invention to find a new type of hinge with defined halt positions, which is capable of overcoming the above-said disadvantages, and in particular which provides a sealing system easy to manufacture and mount, which is capable of keeping the hinge in a secure position when it is in the desired preset position, with no limitation to the borne load, and which it is independent of the environment in which it is used.
The above-said object is achieved through a hinge for door support and maneuvering, consisting of two wing elements, provided with means for fastening to a frame part and to a door part, respectively, as well as mutual-hinging means in a pivoting area, said means consisting of appendixes projecting from said wing elements, wherein said appendixes are shaped as a hollow cylindrical body characterized in that at least one of said appendixes of said wings has axial grooves provided on the internal surface, said grooves being apt to accommodate a thrust element inside a pivot member of said wing elements and protruding from said pivot element. The dependent claims refer to preferential feature.